Polymeric coatings and composites are commonly used to protect a substrate from wear and environmental exposure. Common uses are seen in articles of manufacture in the military, aerospace and petroleum industries. These types of coatings and composites are particularly useful where high strength, stiffness, low weight and/or environmental stability are required. The integrity of a coating or composite can be compromised by many things, such as, fatigue, impact or scratch damage, which can expose the underlying substrate to a corrosive environment. Corrosion reduces the mechanical performance of substrates, which results in timely and expensive repairs. Zinc phosphate polymeric coatings are commonly used in industry to protect steel substrates, but they only slow down corrosive damage.
Numerous approaches have been studied to develop autonomic, self-healing coatings. These so-called smart coatings can protect a substrate from wear and environmental exposure. Examples of these approaches are described in U.S. Pat. Nos. 9,108,364, 7,723,405, 7,569,625, 7,566,747, 7,192,993 and 6,858,859, and U.S. Patent Publication Numbers 2014/0272364, 2014/0363091, 2013/0017405, 2011/0293958 and 2008/0299391. However, the smart coatings described in the field suffer from significant chemical and mechanical limitations, which make them less desirable to use in many situations. For example, nearly all the reported synthetic self-healing strategies require some form of intervention after mechanical damage has been inflicted to initiate the healing process and repair the damage. The current approaches can entail the expenditure of significant external energy, possess limited life-spans or are limited to modest temperatures for autonomic functionality. A large number of reported coatings employ specialty chemicals, which are often expensive, limited to narrow uses and provide less than ideal results in many situations.
Accordingly, there is a need for improved autonomic, self-healing coatings. In this patent, we describe a novel photo-curable self-healing coating system to protect a material. The system is autonomic, self-powered, stable and broadly adaptable to work on a variety of different substrates under different environmental conditions.